Biodiversity estimation of the western region of Ghana using arthropod mean morphospecies abundance

Abstract

There is a global consensus on the fact that human activities are increasingly eroding biodiversity, especially in many ecologically rich regions of the world. Quantifying these biodiversity losses over large administrative areas, along with the impacts of the respective driving factors is necessary for biodiversity conservation. In this study, we used readily available spatial data on infrastructure, fragmentation, and land use together with ecological data on terrestrial arthropods (as species surrogate) to carry out spatial assessment and mapping of biodiversity values in the Western Region of Ghana, a highly degraded part of the West African biodiversity hotspot. Compared with its pristine condition, our results show that the region has a remaining mean species abundance (MSA) of approximately 52%, indicating a loss of 48% due to anthropogenic activities (mainly cocoa and oil palm farming). Areas of national protection (i.e. national parks and forest reserves) did not prove to have much promise for biodiversity conservation in the region since many were found to have low MSA values. Moreover, according to our arthropod data, no areas of high MSA values were found outside protected areas. However, because the thick, continuous, structurally complex canopies of these orchards responsible for the biodiversity loss provide natural connectivity between protected reserves, diversification of understory vegetation and a reduction in the use of agrochemicals particularly weedicides and pesticides may yield significant conservation outcomes.